Tightly fitted ceramic insulator on large area electrode

ABSTRACT

Embodiments of the invention generally include shield frame assembly for use with a showerhead assembly, and a showerhead assembly having a shield frame assembly that includes an insulator that tightly fits around the perimeter of a showerhead in a vacuum processing chamber. In one embodiment, a showerhead assembly includes a gas distribution plate and a multi-piece frame assembly that circumscribes a perimeter edge of the gas distribution plate. The multi-piece frame assembly allows for expansion of the gas distribution plate without creating gaps which may lead to arcing. In other embodiments, the insulator is positioned to be have the electric fields concentrated at the perimeter of the gas distribution plate located therein, thereby reducing arcing potential.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of U.S. Provisional Application Ser. No.61/346,907, filed May 21, 2010 (Attorney Docket No. APPM/15224L), whichis incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention generally relates to an electrode, such as a showerheadassembly, having a tightly fitted ceramic insulator.

2. Description of the Prior Art

In large area, rectangular PECVD chambers used for processing substrateslarger than 1.5 meter square, the tendency to experience arcing aroundthe perimeter of the driven electrode is greater than smaller chambersoperating under the same intrinsic processing conditions, such as RFfrequency and power density, electrode spacing, pressure and gaschemistry. For chambers having electrodes on the order of two to threemeters in two dimensions, arcing may be experienced at such low appliedRF power levels that useful films and/or sufficiently useful depositionrates and commercial productivity cannot be achieved.

Thus, there is a need for an improved electrode suitable for use inlarge area PECVD chambers and the like.

SUMMARY OF THE INVENTION

Embodiments of the invention generally include shield frame assembly foruse with a showerhead assembly, and a showerhead assembly having ashield frame assembly that includes an insulator that tightly fitsaround the perimeter of a showerhead in a vacuum processing chamber. Inone embodiment, a multi-piece frame assembly for circumscribing aperimeter edge of the gas distribution plate showerhead assembly isprovided. The multi-piece frame assembly includes a first elongatedframe member having a hole in a first end and a slot in a second end, asecond short elongated frame member having a hole in a first end and aslot in a second end, a first long elongated frame member having a holein a first end and a slot in a second end, and a second long elongatedframe member having a hole in a first end and a slot in a second end.

In another embodiment of the invention, a showerhead assembly includes agas distribution plate and a multi-piece frame assembly. The multi-pieceframe assembly circumscribes a perimeter edge of the gas distributionplate. The multi-piece frame assembly includes a first frame member anda second frame member. The first frame member has a free end abutting afixed end of the second frame member.

In another embodiment, the showerhead assembly includes an insulativeframe assembly circumscribing a perimeter edge of a gas distributionplate. A conducting element is disposed in the insulative frame assemblyand electrically coupled to the gas distribution plate.

The objective of the present invention will no doubt become obvious tothose of ordinary skill in the art after reading the following detaileddescription of the preferred embodiment, which is illustrated infollowing figures and drawings.

BRIEF DESCRIPTION OF THE APPENDED DRAWINGS

The teachings of the present invention can be readily understood byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIG. 1 depicts a partial sectional view of one embodiment of a PECVDprocessing chamber having a shield frame assembly;

FIG. 2 is a bottom view of one embodiment of the shield frame assemblymounted to a gas distribution plate assembly;

FIG. 3 depicts a shield frame assembly and gas distribution plateassembly of FIG. 2 in a heated condition;

FIGS. 4A-C are side and bottom views of an interface of the shield frameassembly of FIG. 2 in cooled and heated conditions;

FIGS. 5A-F depict exemplary sectional profiles of various embodiments ofa shield frame assembly;

FIG. 6 is a plan view of another embodiment of a shield frame assembly.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is to be noted, however, that the appended drawingsillustrate only typical embodiments of this invention and are thereforenot to be considered limiting of its scope, for the invention may admitto other equally effective embodiments.

DETAILED DESCRIPTION

Embodiments of the invention generally include a shield frame assemblythat includes a multi-piece insulator that tightly fits around theperimeter of a PECVD showerhead assembly. The multi-piece insulator isconfigured to maintain a tight fit during thermally-induced expansionand contraction of the showerhead assembly, thereby minimizing arcingpotential. Additionally, the multi-piece insulator functions to coverand seal the perimeter of the showerhead to prevent arcing to adjacentchamber components. In one embodiment, the shield frame assemblyprevents arcing by physically covering the perimeter of the showerheadassembly with an insulating material. The insulating material may beceramic or other suitable material. Additionally, in other embodiments,the perimeter of the showerhead assembly and/or multi-piece ceramicinsulator includes a radius to reduce electric field concentrations,which additionally reduces the potential of arcing. In otherembodiments, a conducting element is present in the shield frameassembly which is electric connected to or part of the showerheadassembly such that the conducting element operates at essentially thesame voltage of the showerhead assembly, thereby reducing the electricfield on the exposed perimeter of the showerhead assembly. Althoughembodiments of the invention are illustratively described with referenceto a PECVD showerhead assembly, it is contemplated that the inventionmay be utilized in other plasma-assisted processes such as CVD, ALD,etching and the like. It is also contemplated that the shield frameassembly may be utilized on other quadrilateral objects having differentcoefficients of thermal expansion relative to the shield frame assembly.

FIG. 1 depicts a partial sectional view of one embodiment of aprocessing chamber 100 having a shielded showerhead assembly 114. Theprocessing chamber 100 includes a chamber body 102 coupled to an RFpower source 124 and gas panel 122. The chamber body 102 includes walls104 and a lid 106 which are generally fabricated from a conductivematerial. The chamber body 102 confines a processing region 160 above asubstrate support 132 on which a substrate 130 is processed. The backingplate 110 is disposed on the lid 106. An insulator 108 is disposedbetween the backing plate 110 and the lid 106 to provide electricalisolation.

The showerhead assembly 114 is suspended below the backing plate 110 bya bracket 112. The showerhead assembly 114 generally includes a gasdistribution plate 116 and a dielectric shield frame assembly 118.Process and/or cleaning gas is delivered from the gas panel 122 througha gas channel 120 through the backing plate 110 to provide gas into theinterstitial space between the gas distribution plate 116 and thebacking plate 110. Gas in the interstitial space flows through aplurality of gas passages 140 formed through the gas distribution plate116 and into the processing region 160 defined between a bottom 138 ofthe gas distribution plate 116 and the substrate 130 supported on thesubstrate support 132. RF power provided through a matching circuit 126to the gas distribution plate 116 energizes the gases disposed betweenthe gas distribution plate 116 and the substrate 130 to maintain aplasma to facilitate deposition on the substrate 130.

The edge of the substrate 130 is covered by a shadow frame 128 toprevent deposition along the perimeter of the substrate 130 duringprocessing. The shadow frame 128 and/or substrate support 132 iselectrically coupled to the walls 104 of the chamber body 102 by aground RF return path 134, such as a conductive strap. The chamber walls104 additionally include a shadow frame support 136 which supports andlifts the shadow frame 128 off of the substrate support 132, and thesubstrate support 132 is lowered to facilitate substrate transfer. RFpower traveling along the surface of the chamber walls 104 and lid 106is returned to the RF power source 124 through a bracket 146 and cover148.

The gas distribution plate 116 generally includes a step 150 along itsperimeter. Corners 154 formed by an inner wall 152 of the step 150intersecting the bottom 138 of the gas distribution plate 116 generallyhave high electric fields due to their geometry. To prevent arcing atthese locations, the dielectric shield frame assembly 118 is disposed instep 150 and tightly fitted against the inner wall 152. As the highconcentration electric fields produced along the inner wall 152 arelocated in the dielectric material of the shield frame assembly 118,arcing between the gas distribution plate 116 and grounded chambercomponents such as the lid 106 and/or chamber walls 104 is greatlyreduced. The dielectric shield frame assembly 118 is secured to the gasdistribution plate 116 by fasteners or other suitable method (describedfurther below). The fasteners are configured to allow the shield frameassembly 118 to accommodate thermal expansion and contraction of the gasdistribution plate 116, while maintaining little or no gap between theinner wall 152 of the gas distribution plate 116 and the dielectricshield frame assembly 118, and also little or no gap between thecomponents of the shield frame assembly itself.

FIG. 2 depicts a bottom view of one embodiment of the shield frameassembly 118. The shield frame assembly 118 comprises at least fourframe members arranged in a quadrilateral ring. In the embodimentdepicted in FIG. 2, the shield frame assembly 118 includes a short framemember 202, a long frame member 252, a short frame member 254 and a longframe member 256. The short frame members 202, 254 are elongated andhave a parallel orientation. The long frame members 252, 256 areelongated and have a parallel orientation that is substantiallyperpendicular to the orientation of the short frame members 202, 254.Each of the frame members 202, 252, 254, 256 have a fixed end which issecured to the gas distribution plate 116 and a free end which issecured to the gas distribution plate 116 in a manner that permits thegas distribution plate to move relative to the frame member in responseto thermal expansion and contraction of the gas distribution plate 116.

In the embodiment depicted in FIG. 2, the short frame member 202 has asubstantially rectangular form, having a fixed end 204, a free end 206,an outer long side 208 and an inner long side 210. The inner long side210 abuts the inner wall 152 of the gas distribution plate 116. Theouter long side 208 has an orientation generally parallel to the innerlong side 210. The fixed end 204 has a hole 216 formed therethroughwhich accepts a static pin 218 which secures the short frame member 202to the gas distribution plate 116. The hole 216 is dimensioned to have aclose fit to the static pin 218, such that the short frame member 202has little or no motion relative to the static pin 218 which isthreaded, press fit or otherwise secured to the gas distribution plate116. In one embodiment, the static pin 218 is engaged with a threadedhole 230 (seen in FIG. 5A) formed in the gas distribution plate 116.

The free end 206 of the short frame member 202 is disposed opposite thefixed end 204. A slot 212 is formed through the short frame memberproximate the free end 206. The slot 212 has an orientation generallyparallel with the orientation of the long sides 208, 210 and may bealigned with a hole 216 formed through the fixed end 204. A guide pin214 is disposed through the slot 212 to slideably secure the free end206 of the short frame member 202 to the gas distribution plate 116. Theguide pin 214 and slot 212 have a clearance fit which allows the freeend 206 of the short frame member 202 to move in a direction parallelwith the orientation of the slot 212 and long sides 208, 210, whilemaintaining a close fit between the inner long side 210 and the innerwall 152 of the gas distribution plate 116.

The long frame member 252 includes a fixed end 264, a free end 266, anouter long side 268 and an inner long side 270. The ends 264, 266 andsides 268, 270 are generally of the long frame member 252 have anorientation similar to as described with the short frame member 202. Thefixed end 264 of the long frame member 252 abuts the inner long side 210of the short frame member 202 proximate the free end 206 at an interface220. A static pin 218 secures the fixed end 264 of the long frame member252 to the gas distribution plate 116, which a guide pin 214 disposedthrough a slot 212 secure the free end 266 to the gas distribution plate116 as described above with reference to the short frame member 202.Since the fixed end 264 of the long frame member 252 is pinned in asubstantially stationary position relative to the gas distribution plate116, the free end 206 of the short frame member 202 is free to slideacross the fixed end 264 of the long frame member 252 without creating agap at the interface 220 of the abutting portions of the fixed end 264of the long frame member 252 and the inner long side 210 of the shortframe member 202.

The short frame member 254 is substantially identical to the short framemember 202. The short frame member 254 has a substantially rectangularform, having a fixed end 274, a free end 276, an outer long side 278 andan inner long side 280. The inner long side 280 abuts the inner wall 152of the gas distribution plate 116. The outer long side 278 has anorientation generally parallel to the inner long side 280. The fixed end274 has a hole 216 formed therethrough which accepts a static pin 218which secures the short frame member 254 to the gas distribution plate116. The hole 216 is dimensioned with a close fit to the static pin 218,such that the short frame member 254 has little or no motion relative tothe static pin 218 which is threaded, press fit or otherwise secured tothe gas distribution plate 116. In one embodiment, the static pin 218 isengaged with a threaded hole 230 formed in the gas distribution plate116.

The fixed end 274 of the short frame member 254 abuts the inner longside 270 of the long frame member 252 proximate the free end 266 at aninterface 222. Since the fixed end 274 of the short frame member 254 ispinned in a substantially stationary position relative to the gasdistribution plate 116, the free end 266 of the long frame member 252 isfree to slide across the fixed end 274 of the short frame member 254without creating a gap at the interface 222 of the abutting portions ofthe fixed end 274 of the short frame member 254 and the inner long side270 of the long frame member 252.

The free end 276 of the short frame member 254 is disposed opposite thefixed end 274. A slot 212 is formed through the short frame memberproximate the free end 276. The slot 212 has an orientation generallyparallel with the orientation of the long sides 278, 280 and may bealigned with a hole 216 formed through the fixed end 274. A guide pin214 is disposed through the slot 212 to slideably secure the free end276 of the short frame member 254 to the gas distribution plate 116. Theguide pin 214 and slot 212 have a clearance fit which allows the freeend 276 of the short frame member 254 to move in a direction parallelwith the orientation of the slot 212 and long sides 278, 280, whilemaintaining a close fit between the inner long side 280 and the innerwall 152 of the gas distribution plate 116.

The long frame member 256 is substantially identical to the long framemember 252. The long frame member 256 includes a fixed end 284, a freeend 286, an outer long side 288 and an inner long side 290. The ends284, 286 and sides 288, 290 are generally of the long frame member 256have an orientation similar to as described with the long frame member256. The long frame member 256 is coupled to the gas distribution plate116 by a static pin 218 disposed through a hole 216 and a guide pin 214disposed through a slot 212. The free end 286 of the long frame member256 abuts the fixed end 204 of the short frame member 202 proximate thefree end 286 at an interface 226. Since the fixed end 204 of the shortframe member 202 is pinned in a substantially stationary positionrelative to the gas distribution plate 116, the inner long side 290 ofthe long frame member 256 is free to slide across the fixed end 204 ofthe short frame member 202 without creating a gap at the interface 226of the abutting portions of the fixed end 204 of the short frame member202 and the inner long side 290 of the long frame member 256.

The fixed end 284 of the long frame member 256 abuts the inner long side280 of the short frame member 254 proximate the free end 276 at aninterface 224. Since the fixed end 284 of the long frame member 256 ispinned in a substantially stationary position relative to the gasdistribution plate 116, the free end 276 of the short frame member 254is free to slide across the fixed end 284 of the long frame member 256without creating a gap at the interface 224 of the abutting portions ofthe fixed end 284 of the long frame member 256 and the inner long side280 of the short frame member 254.

As discussed above, the frame members 254, 252, 254, 256 accommodatethermal expansion of the gas distribution plate 116 from a coldcondition, as illustrated in FIG. 2, to a hot condition, as illustratedin FIG. 3. As further shown in the detail of the interface 224 depictedin FIGS. 4A-4B, the fixed end 284 of the long frame member 256 issubstantially fixed against the inner long side 280 of the short framemember 254, as illustrated in FIG. 4C, as the gas distribution plate 116expands from a cold condition, as illustrated in FIG. 4A, to a hotcondition, as illustrated in FIG. 4B, because of the proximately (e.g.,closeness) of the relative position of the static pin 218 to the guidepin 214. The motion of the long frame member 256 relative to the shortframe member 254 can be seen in the relative change of position of thelong frame member 256 to the free end 276 of the short frame member 254,and the change in the position of the guide pin 214 in the slot 212 fromthe inner end 232 of the slot 212 to the outer end 234 of the slot 212,which is indicative of the expansion of the gas distribution plate 116which increases the distance between the holes formed in the gasdistribution plate 116 which accept the guide pins 214, 218 along acommon edge of the gas distribution plate 116.

FIGS. 5A-F depict partial sectional views of the profile, the shieldframe assembly and gas distribution plate. As the corner of the gasdistribution plate concentrates the electric field at the perimeter ofthe gas distribution plate when the gas distribution plate is powered,the profile of the shield frame assembly may be designed to eitherminimize the field and/or position of the electric field concentrationwithin the insulative material comprising the shield frame assembly suchthat the potential for arcing between the gas distribution plate andother components, such as the chamber wall, is minimized.

FIG. 5A depicts one embodiment of a profile for the long frame member252 of the shield frame assembly 118. Other frame members of the shieldframe assembly 118 may be similarly configured. The long frame member252 includes a body 508 having an inwardly extending lip 502. The lip502 extends to a tip 506 that is above and covering a portion of thebottom 138 of the gas distribution plate 116. Since the lip 502 coversthe corner 154 of the gas distribution plate 116, the electric fieldconcentrated at the corner 154 is buried in the long frame member 252thereby substantially reducing arcing potential between the gasdistribution plate 116 and the chamber body 102 and/or other chambercomponent.

FIG. 5B depicts another embodiment of a profile for a long frame member500B of the shield frame assembly 118. Other frame members of the shieldframe assembly 118 may be similarly configured. The long frame member500B includes a body 508 having an inwardly extending tapered lip 512.The lip 512 tapers from a top surface 514 of the body 508 that is abovethe bottom 138 of the gas distribution plate 116. Since the lip 512covers the corner 154 of the gas distribution plate 116 and the topsurface 514 of the body 508 is spaced above the bottom 138 of the gasdistribution plate 116, the electric field concentrated at the corner154 is buried in the long frame member 500B, thereby substantiallyreducing arcing potential between the gas distribution plate 116 and thechamber body 102 and/or other chamber component.

FIG. 5C depicts another embodiment of a profile for a long frame member500C of the shield frame assembly 118. Other frame members of the shieldframe assembly 118 may be similarly configured. The long frame member500C includes a body 508 having an inwardly extending lip 522. The lip522 is generally coplanar with a top surface 514 of the body 508 that issubstantially coplanar with the bottom 138 of the gas distribution plate116. The lip 522 extends to an end 524, and this returns to the body 508through a curved surface 520. The profile, or curvature, of the surface520 is selected to mate with the shape of the corner 154, shown in FIG.5C as having radius. The radius of the corner 154 serves to reduce theelectric field concentrated at the corner 154. Since the lip 522 coversthe curved corner 154 of the gas distribution plate 116, the reducedelectric field concentrated at the curved corner 154 is still buried inthe long frame member 500C, thereby substantially reducing arcingpotential between the gas distribution plate 116 and the chamber body102 and/or other chamber component.

FIG. 5D depicts another embodiment of a profile for a long frame member500D of the shield frame assembly 118. Other frame members of the shieldframe assembly 118 may be similarly configured.

In the embodiment depicted in FIG. 5D, a top surface 514 of a body 508of the long frame member 500D extends beyond the bottom 138 of the gasdistribution plate 116. Thus, even through the inner edge 530 of thebody 508 does not mate with the entire profile of the top curved corner154, the reduced electric field concentrated at the curved corner 154 isstill buried below the elevated top 514 of the long frame member 500D,thereby substantially reducing arcing potential.

FIG. 5E depicts another embodiment of a profile for a long frame member500E of the shield frame assembly 118. Other frame members of the shieldframe assembly 118 may be similarly configured. In the embodimentdepicted in FIG. 5E, a body 508 of the long frame member 500E issubstantially coplanar with the bottom 138 of the gas distribution plate116. The long frame member 500E includes a lip 522 substantially matingwith a rounded corner 154 similar to as described with reference to thelong frame member 500C. The long frame member 500E additionally includesa slot 540 extending from a bottom surface 544 of the body 508 towardthe top surface 514. A conducting element 542 that is electricallycoupled to the gas distribution plate 116 is disposed in the slot 540 orotherwise buried in the body 508 of the long frame member 500E. The slot540 extends along the length of the long frame member 500E. Theconducting element 542 operates at essentially the same voltage of thegas distribution plate 116, thereby reducing the electrical field at theexposed corner 154 of the showerhead assembly, additionallyconcentrating the electric field lines substantially within the body508, thereby substantially reducing arcing potential. In the embodimentdepicted in FIG. 5E, the conducting element 542 is depicted as a tabextending from the gas distribution plate 116 into the long frame member500E. It is contemplated that the conducting element 542 may have otherconfigurations buried within otherwise interleaving with the materialcomprising the long frame member 500E in a manner that substantiallyreduces arcing potential.

FIG. 5F depicts another embodiment of a profile for a long frame member500F of the shield frame assembly 118. Other frame members of the shieldframe assembly 118 may be similarly configured. The long frame member500F is configured similar to the long frame member 500E describedabove, including a slot 540 which accepts a conducting element 542,except wherein the top surface 514 of the body 508 extends beyond thebottom 138 of the gas distribution plate 116. Although a lip is notshown in the embodiment depicted in FIG. 5F, it is contemplated that alip such as the lip 522 and/or the lip 502 or the lip 512 may beutilized to cover the corner 154 to enhance the reduction of arcingpotential.

FIG. 6 is a plan view of another embodiment of a shield frame assembly600. The shield frame assembly 600 is substantially similar to theshield frame assembly 118 and includes a short frame member 602, a longframe member 606, a short frame member 604 and a long frame member 608.The short frame members 602, 604 are elongated and have a parallelorientation. The long frame members 606, 608 are elongated and have aparallel orientation that is substantially perpendicular to theorientation of the short frame members 602, 604. Each of the framemembers 602, 604, 606, 608 have a fixed end 632 which is secured to thegas distribution plate 116 (not shown in FIG. 6) and a free end 630which is secured to the gas distribution plate 116 in a manner thatpermits the gas distribution plate to move relative to the frame memberin response to thermal expansion and contraction of the gas distributionplate 116.

Each of the frame members 602, 604, 606, 608 includes an outer edge 610and an inner edge 622. The outer edge 610 of the frame members 602, 604,606, 608 may have a linear orientation. The inner edges 622 of theshield frame assembly 600 differs from the inner edges of shield frameassembly 118 in that the inner edges 622 of each of the frame members602, 604, 606, 608 has a concave portion 612. The concave portion 612 ofthe inner edge 622 is illustrated compared to a linear dashed referenceline 614 extending from the inside corners of the frame members 602,604, 606, 608. The concave portion 612 of the inner edges 622 allows asubstantially uniform gap to be maintained between the shield frameassembly 600 and the gas distribution plate 116 as the center portionsof the gas distribution plate 116 expand outward further than the cornerportions of the gas distribution plate 116 once heated. Thus, theconcave portion 612 of the inner edges 622 minimizes potential rubbingwith the gas distribution plate 116 and particle generation.

Each of the inner edges 622 also includes a linear surface portion 618located at the free end 630 of the frame member in which the slot 212 isformed. The linear surface portion 618 is generally co-linear with thereference line 614 extending from the inside corners of the framemembers 602, 604, 606, 608. The linear surface portion 618 provides aflat surface that slides against an end 620 of the fixed end 632,thereby minimizing gaps between adjacent frame members 602, 604, 606,608 as the shield frame assembly 600 and gas distribution plate 116expend and contract due to heating and cooling.

Thus, showerhead assembly has been provided that includes an insulativeshield frame assembly that tightly fits around the perimeter of ashowerhead. Advantageously, the insulative shield frame assembly isconfigured to maintain a tight fit during thermally-induced expansionand contraction of the showerhead, thereby minimizing arcing potential.Additionally, the insulative shield frame assembly functions to coverand seal the perimeter of the showerhead to prevent arcing to adjacentchamber components. Furthermore, a conducting element is present in someembodiments of the shield frame assembly which is electric connected toor part of the showerhead such that the conducting element operates atessentially the same voltage of the showerhead, thereby reducing theelectric field on the exposed perimeter of the showerhead.

With the example and explanations above, the features and spirits of theembodiments of the invention are described. Those skilled in the artwill readily observe that numerous modifications and alterations of thedevice may be made while retaining the teaching of the invention.Accordingly, the above disclosure should be construed as limited only bythe metes and bounds of the appended claims.

1. A multi-piece frame assembly for circumscribing a perimeter edge of agas distribution plate, comprising: a first short elongated frame memberhaving a hole in a first end and a slot in a second end; a second shortelongated frame member having a hole in a first end and a slot in asecond end; a first long elongated frame member having a hole in a firstend and a slot in a second end; and a second long elongated frame memberhaving a hole in a first end and a slot in a second end.
 2. Themulti-piece frame assembly of claim 1, wherein the first short elongatedframe member comprises: an inner edge and an outer edge, the inner edgehaving a concave portion.
 3. The multi-piece frame assembly of claim 2,wherein the inner edge of the first short elongated frame membercomprises: a linear surface portion.
 4. The multi-piece frame assemblyof claim 3, wherein the linear surface portion of the inner edge isdisposed adjacent the slot of the first short elongated frame member. 5.The multi-piece frame assembly of claim 1, wherein the slot of the firstshort elongated frame member has an orientation aligned parallel with along side of the first short elongated frame member.
 6. The multi-pieceframe assembly of claim 1, wherein the first long elongated frame membercomprises: a body having an inwardly extending lip.
 7. The multi-pieceframe assembly of claim 1, wherein the first long elongated frame membercomprises: a body having an inwardly extending tapered lip.
 8. Themulti-piece frame assembly of claim 1, wherein the first long elongatedframe member comprises: a body having an inwardly extending lip, whereinthe lip being coplanar with a top surface of the body and extending toan end, the end returning to the body through a curved surface.
 9. Themulti-piece frame assembly of claim 1, wherein the first long elongatedframe member comprises: a body having a lip and a slot extending from abottom surface of the body toward a top surface of the body.
 10. Themulti-piece frame assembly of claim 9, wherein the slot extends along alength of the first long elongated frame member.
 11. The multi-pieceframe assembly of claim 1, wherein the frame members are fabricated fromceramic.
 12. A showerhead assembly, comprising: a gas distributionplate; and a multi-piece frame assembly circumscribing a perimeter edgeof the gas distribution plate, the multi-piece frame assembly comprisinga first frame member having a free end abutting a fixed end of a secondframe member.
 13. The showerhead assembly of claim 12, wherein the framemembers are fabricated from ceramic.
 14. The showerhead assembly ofclaim 12, wherein the free end of the first frame member furthercomprises: a slot having a guide pin disposed therethrough and securingthe free end to the gas distribution plate.
 15. The showerhead assemblyof claim 12, wherein the first frame member further comprises: a fixedend opposite the free end, the fixed end of the first frame memberhaving a hole having a static pin disposed therethrough and securing thefixed end of the first frame member to the gas distribution plate. 16.The showerhead assembly of claim 12, wherein the showerhead assemblyfurther comprises: a conducting element disposed in the first framemember of the multi-piece frame assembly and electrically coupled to thegas distribution plate.
 17. A showerhead assembly comprising: a gasdistribution plate; an insulative frame assembly circumscribing aperimeter edge of the gas distribution plate; and a conducting elementdisposed in the insulative frame assembly electrically coupled to thegas distribution plate.
 18. The showerhead assembly of claim 17, whereinthe conducting element is part of the gas distribution plate.
 19. Theshowerhead assembly of claim 18, wherein the conducting element extendsfrom the gas distribution plate into a slot formed in the insulativeframe assembly.
 20. The showerhead assembly of claim 17, wherein theinsulative frame assembly further comprises: a first frame member havinga free end; and a second frame member having an orientationperpendicular to the first frame member, the second frame member havinga fixed end abutting the free end of the first frame member.